BROWN, RUGOSE CORALS 
57 
practically filling the whole interior of the corallite. Figure 9, from a still 
later stage, shows the septa more fully developed and more nearly radially 
placed. The septa at this stage are not as thick, and the interspetal spaces 
are larger and more open. In figures 8 and 9, the tertiary septa are indi¬ 
cated by the centers of calcification, but they do not project beyond the wall 
into the calyx. Figure 10 is from a section taken so that it shows in its center 
the base of the open cup. Even at this late stage of the individual develop- 
Figs. 7-10. Streptelasma corniculum. X 4. 
ment the great prominence of the four primary septa is distinctly shown. 
The tertiary septa have also appeared projecting beyond the wall, one be¬ 
tween each fully developed septum of the primary and secondary cycles. 
In no case do the septa meet and unite in the center to form a pseudocolumella. 
After they are fully developed, they are apparently free at the center. Until 
fully developed, the inner margin is frequently attached to the ventral 
side of the next preceding septum. 
